The WIV handled those novel viruses at BSL-2, not BSL-4. Dr. Shi acknowledged this explicitly in her interview with Science, linked below. Even Ralph Baric (who originated many of the techniques that the WIV scaled up, and whose own research was controversial long before the pandemic) has said that was an unacceptable risk.
https://web.archive.org/web/20210727042832/https://www.scien...
If SARS-CoV-2 arose from a research accident, then it was probably from an American-funded Chinese lab, using techniques developed primarily by an American. So I don't see the political benefit to either country in entertaining that possibility, though I do see a benefit to both countries to downplaying it (as seems to have occurred).
Long before the pandemic, a small subset of virologists and adjacent scientists advocated strongly for certain high-risk research on potential human pandemic pathogens, including laboratory enhancement of existing viruses (gain of function) and hunting of novel viruses from nature. That work was highly controversial, to the point that a three-year moratorium on funding was imposed, ending in 2017. Racaniello was among those advocates; so while he's certainly better-informed than the average person, he also faces a massive conflict of interest. I don't see why you'd trust him over the countless well-credentialed scientists who consider the origin of SARS-CoV-2 to be an open question.